Recent Advances in Organic Synthesis Based on N,N-Dimethyl Enaminones

Synthesis ◽  
2020 ◽  
Author(s):  
Fuchao Yu ◽  
Jiuzhong Huang
Keyword(s):  
Double Bond ◽  
Organic Synthesis ◽  
Bond Cleavage ◽  
Building Blocks ◽  
Chemical Transformations ◽  
Methyl Ketones ◽  
Comprehensive Overview ◽  
The Past ◽  
Leaving Group ◽  
Group A

AbstractEnaminones are gaining increasing interest because of their unique properties and their importance in organic synthesis as versatile building blocks. N,N-Dimethyl enaminones offer a better leaving group (a dimethylamine group) than other enaminones, and allow further elaboration via a range of facile chemical transformations. Over the past five years, there have been an increasing number of reports describing the synthetic applications of N,N-dimethyl enaminones. This review provides a comprehensive overview on the synthetic applications of N,N-dimethyl enaminones that have been reported since 2016.1 Introduction2 Direct C(sp2)–H α-Functionalization2.1 Synthesis of α-Sulfenylated N,N-Dimethyl Enaminones2.2 Synthesis of α-Thiocyanated N,N-Dimethyl Enaminones2.3 Synthesis of α-Acyloxylated N,N-Dimethyl Enaminones3 Functionalization Reactions via C=C Double Bond Cleavage3.1 Synthesis of Functionalized Methyl Ketones3.2 Synthesis of α-Ketoamides, α-Ketoesters and 1,2-Diketones3.3 Synthesis of N-Sulfonyl Amidines4 Construction of All-Carbon Aromatic Scaffolds4.1 Synthesis of Benzaldehydes4.2 Synthesis of the Naphthalenes5 Construction of Heterocyclic Scaffolds5.1 Synthesis of Five-Membered Heterocycles5.2 Synthesis of Six-Membered Heterocycles5.3 Synthesis of Quinolines 5.4 Synthesis of Functionalized Chromones5.5 Synthesis of Other Fused Polycyclic Heterocycles6 Conclusions and Perspectives

scholarly journals Synthesis and Reactivity of Electron-Deficient 3-Vinylchromones

SynOpen ◽  
2021 ◽  
Vol 05 (03) ◽  
pp. 255-277
Author(s):  
Vyacheslav Y. Sosnovskikh
Keyword(s):  
Double Bond ◽  
Chemical Properties ◽  
Building Blocks ◽  
High Reactivity ◽  
Cycloaddition Reactions ◽  
Chemical Transformations ◽  
Pyrone Ring ◽  
The Past ◽  
Palladium Catalyzed ◽  
First Time

AbstractThe reported methods and data for the synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing­ groups at the exo-cyclic double bond are summarized and systematized for the first time. The main methods for obtaining these compounds are Knoevenagel condensation, Wittig reaction, and palladium-catalyzed cross-couplings. The most important chemical properties are transformations under the action of mono- and dinucleophiles, ambiphilic cyclizations, and cycloaddition reactions. The cross-conjugated and polyelectrophilic dienone system in 3-vinylchromones provides their high reactivity and makes these compounds valuable building blocks for the preparation of more complex heterocyclic systems. Chemical transformations of 3-vinylchromones usually begin with an attack of the C-2 atom and are accompanied by the opening of the pyrone ring followed by recyclization, in which the carbonyl group of chromone, an exo-double bond or a substituent on it can take part. The mechanisms of the reactions are discussed, the conditions for their implementation are described, and the yields of the resulting products are given. This review focuses on an analysis and generalization of the knowledge that has accumulated on the chemistry of electron-deficient 3-vinylchromones, mostly over the past 15 years.1 Introduction2 Synthesis of 3-Vinylchromones3 Reactions with Mononucleophiles4 Reactions with Dinucleophiles5 Ambiphilic Cyclization6 Cycloaddition Reactions7 Other Reactions8 Conclusion

scholarly journals Recent Advances in Palladium-Catalyzed Isocyanide Insertions

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4906
Author(s):  
Jurriën W. Collet ◽  
Thomas R. Roose ◽  
Bram Weijers ◽  
Bert U. W. Maes ◽  
Eelco Ruijter ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Building Blocks ◽  
Insertion Reactions ◽  
Chemical Reagents ◽  
The Past ◽  
Recent Advances ◽  
Recent Developments ◽  
Palladium Catalyzed ◽  
Made In ◽  
Rapid Incorporation

Isocyanides have long been known as versatile chemical reagents in organic synthesis. Their ambivalent nature also allows them to function as a CO-substitute in palladium-catalyzed cross couplings. Over the past decades, isocyanides have emerged as practical and versatile C1 building blocks, whose inherent N-substitution allows for the rapid incorporation of nitrogeneous fragments in a wide variety of products. Recent developments in palladium catalyzed isocyanide insertion reactions have significantly expanded the scope and applicability of these imidoylative cross-couplings. This review highlights the advances made in this field over the past eight years.

Use of enzymes as catalysts to promote key transformations in organic synthesis

1989 ◽  
Vol 324 (1224) ◽  
pp. 577-587 ◽  
Keyword(s):  
Organic Synthesis ◽  
Large Scale ◽  
Immobilized Enzymes ◽  
Building Blocks ◽  
Optically Active ◽  
The Past ◽  
Small Proteins ◽  
Areas Of Interest ◽  
Oxidation Of Benzene ◽  
Reduction Of Ketones

The field of biotransformations has developed rapidly over the past eight years. The use of esterases and lipases is now widespread; these enzymes are of particular importance in the production of optically active building blocks for organic synthesis as well as in large-scale processes involving the transesterification of fats. The latter area (i.e. the catalysis of esterification processes) has stimulated research into the properties of immobilized enzymes and the use of enzymes in low-water systems. In related work, enzymes have been used for the preparation of peptides and small proteins. Redox enzymes have been investigated extensively, particularly with regard to the stereocontrolled reduction of ketones to secondary alcohols. The methods for using commercially available enzymes of this type have become increasingly ‘userfriendly’. The controlled oxidation of hydrocarbon units is another area that has deserved increased attention. For example, oxidation of benzene and simple derivatives by Pseudomonas sp. has been researched by a number of U.K. groups. These recent advances in enzyme-catalysed reactions (using both whole-cell systems and partly purified protein) for the transformation of unnatural substrates is discussed and some areas of interest for the future are outlined.

scholarly journals σ-Bond Hydroboration of Cyclopropanes

2020 ◽  
Author(s):  
Hiroki Kondo ◽  
Shin Miyamura ◽  
Chisa Kobayashi ◽  
Arifin ◽  
Stephan Irle ◽  
...  
Keyword(s):  
Double Bond ◽  
Natural Product ◽  
Organic Synthesis ◽  
Bond Cleavage ◽  
Cross Coupling ◽  
High Reactivity ◽  
Natural Product Synthesis ◽  
Theoretical Studies ◽  
Single Bond

Hydroboration of alkenes is a classical reaction in organic synthesis, in which alkenes react with boranes to give alkylboranes, with subsequent oxidation resulting in alcohols. The double bond (π-bond) of alkenes can be readily reacted with boranes owing to its high reactivity. However, the single bond (σ-bond) of alkanes has never been reacted. To pursue the development of σ-bond cleavage, we selected cyclopropanes as model substrates since they present a relatively weak σ-bond. Herein, we describe an iridium-catalyzed hydroboration of cyclopropanes, resulting in β-methyl alkylboronates. These unusually branched boronates can be derivatized by oxidation or cross-coupling chemistry, accessing “designer” products that are desired by practitioners of natural product synthesis and medicinal chemistry. Furthermore, mechanistic investigations and theoretical studies revealed the enabling role of the catalyst.

scholarly journals C-Lactam Derivatives of Oleanolic Acid. The Synthesis of C-lactam by Beckmann Rearrangement of C-oxime

2011 ◽  
Vol 6 (12) ◽  
pp. 1934578X1100601
Author(s):  
Barbara Bednarczyk – Cwynar
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Oleanolic Acid ◽  
Structure Elucidation ◽  
Beckmann Rearrangement ◽  
Hydroxyl Group ◽  
Chemical Transformations ◽  
Group A ◽  
Derivatives Of ◽  
Carbonyl Function

Oleanolic acid, one of the most known triterpenes, was subjected to different chemical transformations within C-3 β-hydroxyl group, a double bond between C-12 and C-13, and a carboxyl function at C-17 in order to obtain new derivatives. The key compound consists of four six-membered rings (A, B, D, E) and one enlarged ring (C ring) containing a nitrogen atom and a carbonyl function – lactam. This type of derivative can be obtained by Beckmann rearrangement of the appropriate oxime. The lactam can be transformed into thiolactam with the use of Lavesson's reagent. The method is also presented for new derivatives synthesis, as well as their structure elucidation by spectroscopic means.

Alkyne-Forming Furan Fragmentation: A General Method to Convert Furans into Alkynoic Acids

Synlett ◽  
2019 ◽  
Vol 30 (06) ◽  
pp. 642-646
Author(s):  
Jinghan Gui ◽  
Jiachen Deng
Keyword(s):  
Reaction Mechanism ◽  
Double Bond ◽  
Singlet Oxygen ◽  
Natural Product ◽  
Organic Synthesis ◽  
Bond Cleavage ◽  
Historical Context ◽  
Natural Product Synthesis ◽  
Fragmentation Reaction ◽  
General Method

Furans are readily available and highly reactive heterocycles that serve as versatile four-carbon synthons in organic synthesis. Recently, we discovered that furans, upon oxidation with singlet oxygen, can be transformed into alkynes via dual C–C double-bond cleavage. This Synpacts article presents an overview of the historical context and the development of this furan fragmentation reaction. We also discuss its application in natural product synthesis and a plausible reaction mechanism.1 Introduction2 Background of Alkyne-Forming Furan Fragmentation3 Reaction Development4 Conclusion

Cyanoacetylenic alcohols, molecules of interstellar origin in the biomimetic synthesis of life relevant heterocycles, amino acids, nucleobases and nucleosides: towards prebiotic chemistry

Synthesis ◽  
2021 ◽  
Author(s):  
Boris Trofimov ◽  
Anastasiya Mal’kina
Keyword(s):  
Amino Acids ◽  
Organic Synthesis ◽  
Prebiotic Chemistry ◽  
Aqueous Media ◽  
Biomimetic Synthesis ◽  
Hydroxyl Group ◽  
Chemical Transformations ◽  
Molecular Architecture ◽  
The Past ◽  
Derivatives Of

Cyanoacetylenic alcohols, R1R2C(OH)C≡C-CN, the closest derivatives of cyanoacetylene, an interstellar abundant molecule, are now becoming acknowledgeable in modern organic synthesis which tends to mimic nature. Highly reactive C≡C and C≡N bonds in close vicinity of the hydroxyl group makes these molecules a chemical trinity of mutually influencing functions ensuring an endless number of chemical transformations. All reactions of cyanoacetylenic alcohols parallel modern organic synthesis, being biomimetic. They do not need transition metals (and in most cases, the metals at all except for physiologically indispensible Na+, K+), proceed at ambient temperature and often in aqueous media. Fundamentally, these reactions are 100% atom-economic because they are almost exclusively addition processes. Usually, in the cyanoacetylenic alcohols, cyano, acetylene and hydroxyl functions behave as inseparable entity providing the multiple functionalizations of the forming molecules. This allows hydroxyl, carbonyl, carboxylic, imino, amino, amido, cyanoamido, cyano, various P-containing, ether and ester functions, along with the double bonds and different fundamental heterocycles (furans, furanones, pyrazoles, oxazoles, pyridines, pyrimidines, purins, etc.) and diverse polycyclic systems to be integrated in a one molecular architecture. This review focuses on analysis and generalization of the knowledge accumulated in the chemistry of these cyanoacetylenic alcohols, mostly over the past 15 years.

scholarly journals Selective Dealkenylative Functionalization of Styrenes via C-C Bond Cleavage

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianzhong Liu ◽  
Jun Pan ◽  
Xiao Luo ◽  
Xu Qiu ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Double Bond ◽  
Late Stage ◽  
Bond Cleavage ◽  
Fine Chemicals ◽  
The Novel ◽  
Single Bond ◽  
The Past ◽  
Aryl Amines ◽  
Site Selective ◽  
Important Building Block

As a readily available feedstock, styrene with about 25 million tons of global annual production serves as an important building block and organic synthon for the synthesis of fine chemicals, polystyrene plastics, and elastomers. Thus, in the past decades, many direct transformations of this costless styrene feedstock were disclosed for the preparation of high-value chemicals, which to date, generally performed on the functionalization of styrenes through the allylic C-H bond, C(sp2)-H bond, or the C=C double bond cleavage. However, the dealkenylative functionalization of styrenes via the direct C-C single bond cleavage is so far challenging and still unknown. Herein, we report the novel and efficient C-C amination and hydroxylation reactions of styrenes for the synthesis of valuable aryl amines and phenols via the site-selective C(Ar)-C(alkenyl) single bond cleavage. This chemistry unlocks the new transformation and application of the styrene feedstock and provides an efficient protocol for the late-stage modification of substituted styrenes with the site-directed dealkenylative amination and hydroxylation.

scholarly journals Photoredox-catalyzed oxo-amination of aryl cyclopropanes

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Liang Ge ◽  
Ding-Xing Wang ◽  
Renyi Xing ◽  
Di Ma ◽  
Patrick J. Walsh ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Driving Force ◽  
Ring Opening ◽  
Bond Cleavage ◽  
Building Blocks ◽  
Nucleophilic Attack ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
One Pot ◽  
Thermodynamic Driving Force

Abstract Cyclopropanes represent a class of versatile building blocks in modern organic synthesis. While the release of ring strain offers a thermodynamic driving force, the control of selectivity for C–C bond cleavage and the subsequent regiochemistry of the functionalization remains difficult, especially for unactivated cyclopropanes. Here we report a photoredox-coupled ring-opening oxo-amination of electronically unbiased cyclopropanes, which enables the expedient construction of a host of structurally diverse β-amino ketone derivatives. Through one electron oxidation, the relatively inert aryl cyclopropanes are readily converted into reactive radical cation intermediates, which in turn participate in the ensuing ring-opening functionalizations. Based on mechanistic studies, the present oxo-amination is proposed to proceed through an SN2-like nucleophilic attack/ring-opening manifold. This protocol features wide substrate scope, mild reaction conditions, and use of dioxygen as an oxidant both for catalyst regeneration and oxygen-incorporation. Moreover, a one-pot formal aminoacylation of olefins is described through a sequential cyclopropanation/oxo-amination.

Tertiary Enamides: Versatile and Available Substrates in Synthetic Chemistry

2019 ◽  
Vol 16 (1) ◽  
pp. 70-97 ◽  
Author(s):  
Xiaohua Cai ◽  
Mengzhi Yang ◽  
Hui Guo
Keyword(s):  
Chemical Reaction ◽  
Coupling Reaction ◽  
Building Blocks ◽  
Synthetic Chemistry ◽  
The Past ◽  
Recent Advances ◽  
Complex Building ◽  
Group A ◽  
Unique Stability ◽  
Made In

Background: Enamines and their variant enamides as powerful and versatile synthons have attracted great attention in synthetic chemistry. Enamides display unique stability and reduce enaminic reactivity in view of the electron-withdrawing effect of N-acyl group. A great deal of satisfactory achievements in the synthesis and application of enamides has been made in recent years. Especially, tertiary enamides without N-H bond regarded as low reactivity of compounds in the past can act as excellent nucleophiles to react with electrophiles for the construction of various nitrous molecules. </P><P> Objective: This review focuses on recent advances on tertiary enamides in the synthetic strategies and applications including addition, coupling reaction, functionalization and electro- or photo-chemical reaction. Conclusion: Tertiary enamides as electron-deficient nucleophiles display a satisfactory balance between stability and reactivity to offer multiple opportunities for the construction of various functionalized nitrogencontaining compounds. Further exploration of the reactive mechanisms involved tertiary enamides and the development of novel and efficient transformations to generate ever more complex building blocks starting from tertiary enamides are particularly worth pursuing.

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